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    <meta charset="UTF-8">
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    <title>Document</title>
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<body>
    <script>
        //声明变量
        //1.let 变量名不能重复
        // let star = '张三';
        // let star = '李四';

        //2.块级作用域 全局，函数 eval
        // {
        //     let girl = '张三';
        // }
        // console.log(girl);
    </script>
</body>
</html>